Electromagnetic switching device.



D. D. MILLER.

ELECTROMAGNETIC SWlTCHlNG DEVICE.

APPLICATION FILED NOV. 2?. 1916.

Patented July 9, 1918.

vvuvvu 5. r. 5 m v m g H u a 0 UNITED STATES PATENT anion.

DANIEL I). MILLER, OF NEW YORK, N.- Y., ASSIGNOR '10 WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

ELECTROMAGNETIC SI/VITCHINCT DEVICE.

Application filed November 27, 1916.

To all whom it may concern Be it known that I, DANIEL D. MILLER, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Electromagnetic Switching Devices, of which the following is a full, clear, concise, and exact description.

This invention relates to electromagnetic switching devices, and more particularly to such devices operated by alternating current.

An object of this invention is the provision of an eflicient and compact alternating current electromagnetic switching device which will maintain its contacts open or closed as desired without chattering.

In accordance with this invention, a core on which there is an energizing winding is provided with a bifurcated pole piece on one leg of which is a winding or its equivalent for producing phase displacement of a portion of the flux traversing the core, whereby an armature operatively associated with the core is maintained attracted while the current in the energizing winding is passing through zero.

This invention is illustrated in the accompanying drawings, wherein Figure 1 is a perspective of an electromagnetic switching device or relay in which the phase displacement is obtained by means of a closed coil of one turn forming the front head which carries adjustment screws for the contact springs and armature; Fig. 2 is a perspective of the front end of a relay in which the phas displacement winding is in the form of a closed coil of one turn encircling one leg of the bifurcated pole piece outside of the head; Fig. 3 is a View showing the phase displacement winding in series with the energizing winding and a non-inductive resistance in parallel therewith; and Fig. 4: is a modification in which a condenser replaces the non-inductive resistance of Fig.

The general construction of the relay shown in the drawings conforms to that of the relay illustrated in Patent No. 1,121,897 to E. B. Craft, there being a core upon which an energizing winding 51 is mounted between spool heads 49 and 50, preferably of insulating material. To a cross piece 3, formed integrally with the core, is flexibly mounted a U-shaped armature 16 by means of resilient sheet metal strips.

Two forwardly extending contact springs Specification of Letters Patent.

Patented July 9, 1918.

Serial No. 133,600.

23 and 2 1 are carried by and insulated from two brackets a and 5, secured to the cross piece 3. The armature 16 is maintained in its normal position against contact spring 23 by means of a spring as secured to one leg of the armature, the free end of the spring 46 being engaged by an adjusting screw 18, carried by a plate 15 mounted on the pole piece adjacent the spool head 50.

In Fig. 1, the plate 15 is of copper which forms a closed coil of one turn surrounding the leg 56 of the pole piece, the lower portion of the plate 15 being slotted as at 60 to prevent the forming of a coil for the lower leg 57.

In Fig. 2, the plate 15 is preferably of brass, and a ring 61 of copper mounted adjacent the plate 15 forms a closed coil of one turn, surrounding the leg 56.

In Fig. 3, there is shown a coil 62 on the leg 56, connected in series with the energizing winding 51. In parallel with the wind ing 62 is connected a non-inductive resistance 63 which may be wound on the leg 56 with the winding 62. This winding 62 and noninductive resistance 63 may be employed instead of the ring 61, shown in Fig. 2.

In Fig. 4:, there is shown another scheme for causing phase displacement of a portion of the flux traversing the core. In this scheme, the winding 62 on the leg 56 is connected in series with the energizing winding 51 as in Fig. 3, but a condenser 64, instead of the non-inductive resistance 63 is in parallel with the winding 62.

The two legs of the pole piece and the two legs of the armature form two distinct and similar magnetic paths, one of which comprises the leg 56, the upper leg of the armature and the core, and the other of which comprises the leg 57, the lower leg of the armature and the core. A third magnetic path, dissimilar to the two previously mentioned magnetic paths comprises leg 56, a portion of the core, leg 57 and a portion of the free end of the armature. In all of these paths there is, of course, included the air gap between the legs of the pole pieces and the armature. The copper plate 15 of Fig. 1 and the copper ring 61 of Fig. 2, as before explained, form closed coils of one turn in which, when current is traversin the energizing winding, is induced a current out of phase with the current in the energizing winding. In Figs. 3 and 4, the

time constant of winding 62 is different from that of the energizing winding 51. This induced current in the closed coils of Figs. 1 and 2 or the current traversing Winding 62 of Figs. 3 and at produces in the third magnetic path above mentioned a flux out of phase with that traversing the ther two paths.

The flux in this third path causes at the leg 56 of the pole piece a lag of the flux traversing the first mentioned path, whereby, when the flux traversing the second mentioned path is passing through zero, that traversing the first mentioned path will be above zero, thereby maintaining the constant attraction of the armature.

lVhat is claimed is:

1. An alternating current electro-.1nag netie switching device comprising a core having a bifurcated pole piece, an energizing winding for the core, an armature mountedin operative relation to the pole piece, contact springs mounted in position to be controlled by the armature, a conducting plate mounted on and completely surrounding one leg of the bifurcated pole piece and forming a phase displacement winding, and means carried by the plate for adjusting the position of the contact springs.

2. An alternating current electro-magnetic switching device comprising a core having a bifurcated pole piece, an energizing winding for the core, an armature mounted in operative relation to the pole piece, contact springs mounted in position to be controlled by the armature, a conducting plate mounted on and completely surrounding one leg of the bifurcated pole piece and forming a phase displacement winding, and adjustment screws carried by the plate for adjusting the position of the contact springs.

' 3. An alternating current electromagnetic switching device comprising a core having a bifurcated pole piece, an extension on the rear end thereof, an energizing winding for the core, a Ushaped armature flexibly mounted on the core extension and extending substantially parallel with the core with the free end thereof in juxtaposition to the pole piece, contact springs mounted on the core extension extending substantially parallel to the core and controlled by the armature, a conducting plat-e mounted on and completely surrounding one leg of the bifurcated pole piece and forming a phase displacement winding, and adjustment screws carried by the plate for adjusting the position of the contact springs.

In witness whereof, I hereunto subscribe my name this 24th day of November A. D., 1916..

DANIEL D. MILLER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

